JP4770758B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine, and more particularly to a device for controlling the opening / closing timing of an exhaust valve when the internal combustion engine is started.

  In an internal combustion engine, air-fuel ratio feedback control may be performed by detecting an exhaust gas component (for example, oxygen concentration) by placing an air-fuel ratio sensor (for example, oxygen concentration sensor) in the exhaust passage.

  In this case, the sensor element provided in the air-fuel ratio sensor is generally activated while being heated to a predetermined temperature or higher, and the exhaust gas component can be detected. Accordingly, the air-fuel ratio sensor is often provided with a sensor heater for heating the sensor element.

  In the internal combustion engine provided with the air-fuel ratio sensor as described above, the exhaust gas discharged from the internal combustion engine at the time of start-up contains moisture generated during combustion, and the moisture becomes water droplets as described above. There was a case of touching the sensor. Further, after the previous engine stop, the exhaust gas left in the exhaust passage is cooled, so that condensed water is generated, and this condensed water may be scattered when the internal combustion engine is started and may contact the air-fuel ratio sensor. .

  Then, in the sensor element that has become high temperature due to the heating of the sensor heater, damage such as element cracking may occur due to a thermal shock that rapidly cools a portion in contact with water droplets.

  On the other hand, in practice, in many cases, control for restricting energization to the sensor heater is performed until the temperature in the vicinity of the air-fuel ratio sensor in the exhaust passage sufficiently increases. For example, when the outside air temperature at the time of engine start is lower than the outside air temperature threshold, the set temperature for starting the heater is changed to be high, and when the temperature difference between the engine cooling water temperature at the time of engine start and the outside air temperature is larger than the temperature difference threshold A technique (see Patent Document 1) for further increasing the set temperature is known. However, in these prior arts, the start of the air-fuel ratio feedback control is delayed, and there is a possibility that the emission at the start of the internal combustion engine is deteriorated.

On the other hand, at the start of the internal combustion engine, the opening / closing timing of the exhaust valve is advanced to increase the in-cylinder pressure when the intake valve is opened, thereby facilitating the return of compressed gas to the intake system. There is known a technique for stabilizing the combustion during cold start. In this case, as another effect, it is understood that the relatively high temperature gas during or immediately after combustion in the internal combustion engine is discharged as exhaust gas, so that the exhaust temperature can be increased (see, for example, Patent Document 2). ing. Therefore, it can be considered that the temperature in the vicinity of the air-fuel ratio sensor in the exhaust passage is raised early by using this effect. However, conventionally, with this technique, when the cooling water temperature of the internal combustion engine reaches a predetermined value, the variable valve mechanism often starts control to change the opening / closing timing of the exhaust valve to the timing according to the operating state. For this reason, the advance control of the opening / closing valve timing of the exhaust valve is canceled early, and it may be difficult to efficiently raise the temperature of the exhaust passage.
JP 2005-105960 A JP 2002-227630 A JP 2004-353495 A

  An object of the present invention is to quickly disperse water droplets in an exhaust passage at the start-up in an internal combustion engine provided with an air-fuel ratio sensor that is disposed in the exhaust passage and is capable of detecting an air-fuel ratio in a heated state. The object is to provide a technology that can improve the emission at the start of the internal combustion engine by eliminating the air-fuel ratio sensor and accelerating the heating timing of the air-fuel ratio sensor.

In order to achieve the above object, the present invention has the following features. That is, when the internal combustion engine is started, the opening / closing timing of the exhaust valve is set to a starting opening / closing timing that is an advance side of the reference opening / closing timing that is the reference of the opening / closing timing of the exhaust valve after the warm-up is completed. Then, this state is continued until the temperature near the air-fuel ratio sensor in the exhaust passage becomes equal to or higher than the dew point temperature at which the water droplets disappear. Thereafter, the change of the opening / closing timing of the exhaust valve according to the operation state by the variable valve mechanism is started.

More specifically, an air-fuel ratio sensor provided in the exhaust passage of the internal combustion engine and capable of detecting the air-fuel ratio of exhaust in a state activated by heating,
A start time advance means for setting the open / close timing of the exhaust valve at the start of the internal combustion engine to a start time open / close timing that is an advance side of a reference open / close timing that is a reference of the open / close timing of the exhaust valve after completion of warm-up;
A variable valve mechanism capable of changing the opening and closing timing of the exhaust valve;
An operating state corresponding control means for performing an operating state corresponding control for changing the opening and closing timing of the exhaust valve by the variable valve mechanism according to the operating state of the internal combustion engine;
Temperature obtaining means for obtaining a temperature in the vicinity of the air-fuel ratio sensor in the exhaust passage,
When the temperature in the vicinity of the air-fuel ratio sensor acquired by the temperature acquisition means at the time of starting the internal combustion engine is lower than the dew point temperature at which water drops in the exhaust passage disappear, the opening / closing timing of the exhaust valve is set at the time of starting. Maintained at the opening and closing time,
The operating state corresponding control means starts the operating state corresponding control after the temperature in the vicinity of the air-fuel ratio sensor becomes equal to or higher than the dew point temperature .

According to this, when the internal combustion engine is started, the state in which the opening / closing timing of the exhaust valve is advanced from the reference opening / closing timing continues until the temperature in the exhaust passage near the air-fuel ratio sensor becomes equal to or higher than the dew point temperature . Then, it is possible to continue the state in which the temperature of the exhaust gas becomes relatively high by discharging the high-temperature exhaust gas immediately after combustion until the temperature in the vicinity of the air-fuel ratio sensor becomes equal to or higher than the dew point temperature . Therefore, the period until the temperature near the air-fuel ratio sensor becomes equal to or higher than the dew point temperature can be shortened.

  As a result, the start timing of the air-fuel ratio feedback control by the air-fuel ratio sensor can be advanced, and the emission at the start of the internal combustion engine can be improved.

Further, in the present invention, the start time advance means further sets the opening / closing timing of the intake valve at the start of the internal combustion engine as an intake side reference opening / closing timing which is a reference for the opening / closing timing of the intake valve after the warm-up is completed. Set the opening / closing timing at the intake side start on the more advanced side,
The variable valve mechanism can change the opening and closing timing of the exhaust valve and the intake valve,
In the operating state corresponding control, the operating state corresponding control means changes the opening and closing timings of the exhaust valve and the intake valve by the variable valve mechanism according to the operating state of the internal combustion engine,
When the temperature in the vicinity of the air-fuel ratio sensor acquired by the temperature acquisition means at the time of starting the internal combustion engine is lower than the dew point temperature , the opening / closing timing of the exhaust valve is maintained at the opening / closing timing at startup and the intake air The opening / closing timing of the valve may be maintained at the opening / closing timing at the intake side start.

Then, when starting the internal combustion engine, the opening and closing timing of the intake valve and the exhaust valve is advanced from the reference value after warming up to atomize the injected fuel, and the opening and closing timing of the intake valve and the exhaust valve is operated. In an internal combustion engine that is optimized according to the state, it is possible to shorten the period until the temperature near the air-fuel ratio sensor in the exhaust passage becomes equal to or higher than the dew point temperature . As a result, the start timing of the air-fuel ratio feedback control by the air-fuel ratio sensor can be advanced, and the emission at the start of the internal combustion engine can be improved.

  The means for solving the problems in the present invention can be used in combination as much as possible.

  In the present invention, in an internal combustion engine provided with an air-fuel ratio sensor that is disposed in the exhaust passage and can be heated, the scattering of water droplets in the exhaust passage at the time of starting can be eliminated at an early stage. The heating time of the air-fuel ratio sensor can be advanced. As a result, it is possible to improve the emission at the start of the internal combustion engine.

  The best mode for carrying out the present invention will be exemplarily described in detail below with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine 1 and its intake / exhaust system and control system in the present embodiment. The internal combustion engine 1 shown in FIG. 1 obtains output by repeating four cycles of an intake stroke, a compression stroke, an explosion stroke (expansion stroke), and an exhaust stroke. The internal combustion engine 1 forms a cylinder 2 therein. The explosive force of the fuel generated in the cylinder 2 is converted into a rotational force of a crankshaft (not shown) through the piston 3 and the connecting rod 4. The cylinder 2 is connected to an intake port 11 that forms the most downstream portion of the intake passage 5 and an exhaust port 8 that forms the most upstream portion of the exhaust passage 6. The intake port 11 is provided with a fuel injection valve 10 that injects fuel for combustion. The boundary between the intake port 11 and the cylinder 2 is opened and closed by an intake valve 12. The boundary between the exhaust port 8 and the cylinder 2 is opened and closed by an exhaust valve 9.

  The intake valve 12 and the exhaust valve 9 are respectively provided with an intake side variable valve mechanism (hereinafter referred to as an intake side VVT) 17 and an exhaust side variable valve mechanism (hereinafter referred to as an exhaust side VVT) 16. The intake side VVT 17 and the exhaust side VVT 16 can change the phase angles of the intake valve 12 and the exhaust valve 9 within a predetermined range, respectively, by a command from an electronic control unit (ECU) 20. According to such a configuration, by appropriately adjusting the opening phase of at least one of the intake valve 12 and the exhaust valve 9, it is possible to improve driving performance and fuel consumption according to the driving state.

  In addition to the exhaust purification catalyst 7 for exhaust purification, the exhaust passage 6 is provided with an air-fuel ratio sensor 18 for detecting the air-fuel ratio of exhaust passing through the exhaust passage 6 and performing feedback control of the air-fuel ratio. .

  A sensor element (not shown) in the air-fuel ratio sensor 18 is formed of a zirconia tube or the like, and is activated by being heated to a temperature of, for example, 400 ° C. or higher, so that the oxygen concentration of the exhaust gas can be detected. Become.

A sensor heater (not shown) is provided inside the sensor element. Before the air-fuel ratio feedback control is started by detecting the air-fuel ratio in the exhaust, the sensor heater is energized by a command from the ECU 20 to heat the sensor element.

  On the other hand, the intake passage 5 is provided with a throttle valve 14 capable of controlling the amount of intake air. The intake passage 5 is provided with an air flow meter 13 for detecting the amount of intake air introduced.

  The internal combustion engine 1 includes various sensors such as a crank position sensor and an accelerator position sensor (not shown) in addition to the air-fuel ratio sensor 18 and the air flow meter 13 described above. Signals from these various sensors are input to the ECU 20.

  The ECU 20 includes a logical operation circuit including a central processing unit (CPU), a read only memory (ROM), a random access memory (RAM), a backup RAM, and the like, and the fuel injection valve 10 of the internal combustion engine 1 based on signals from various sensors. In addition, various components such as the intake side VVT 17, the exhaust side VVT 16, and the throttle valve 14 are collectively controlled.

  Here, the control of the intake valve 12 and the exhaust valve 9 when the internal combustion engine 1 is started will be described with reference to FIG. FIG. 2 (a) shows the opening / closing timing of a general intake valve 12 and exhaust valve 9 of the internal combustion engine 1 after the warm-up is completed. As shown here, generally, after the warm-up is completed, the intake valve 12 is opened in a range of, for example, -3 degrees with respect to TDC to 67 degrees with respect to BDC. On the other hand, the exhaust valve 9 opens in a range from 56 degrees to BDC to 4 degrees to TDC. The opening / closing valve timings of the intake valve 12 and the exhaust valve 9 shown here correspond to the reference opening / closing timing in this embodiment.

  On the other hand, when the internal combustion engine 1 is started, as shown in FIG. 2B, the opening / closing timings of the intake valve 12 and the exhaust valve 9 are advanced as compared to after the warm-up is completed (see FIG. 2B). Hereinafter, this state is also referred to as “start-up advance state”). Specifically, in the present embodiment, the intake valve 12 opens, for example, in a range from 3 degrees to TDC to 61 degrees to BDC. On the other hand, the exhaust valve 9 opens in a range from 76 degrees to BDC to -16 degrees to TDC. The opening / closing valve timings of the intake valve 12 and the exhaust valve 9 shown here correspond to the opening / closing timing at start in this embodiment.

  Further, in the present embodiment, the initial intake valve 12 is set so that the above-mentioned start-up advance state is realized in the initial state of the intake side VVT 17 and the exhaust side VVT 16 (the state in which the intake side VVT 16 is not operated by a command from the ECU 20). The opening / closing valve timing of the exhaust valve 9 is set, and the system initially set in this way corresponds to the start time advance means in this embodiment.

  In such a starting advance state, the pressure in the cylinder 2 can be increased in the vicinity of TDC, and high-pressure compressed gas can be blown back to the intake port 11 side when the intake valve 12 is opened. There is an effect that the atomization of the fuel injected from the fuel injection valve 10 can be promoted and the combustion stability at the start can be improved.

  In the control of the conventional internal combustion engine, when the internal combustion engine is started, combustion stability is ensured by maintaining the above-mentioned advance state at the time of start, and when the cooling water temperature of the internal combustion engine becomes equal to or higher than a predetermined temperature and the warm-up ends. In this case, using the intake side VVT 17 and the exhaust side VVT 16, the opening / closing timing of the intake valve 12 and the exhaust valve 9 is controlled to a timing at which appropriate driving performance and fuel consumption can be obtained according to the driving state. The control after the warm-up is completed corresponds to the operation state corresponding control in this embodiment, and the ECU 20 that gives commands to the intake side VVT 17 and the exhaust side VVT 16 at this time corresponds to the operation state corresponding control means.

By the way, when the internal combustion engine 1 is in the above-described advance state at the time of start-up, high-temperature combustion gas that has not been sufficiently expanded immediately after combustion can be discharged to the exhaust system. In addition to the effect of improving the combustion stability, it has been found that there is a secondary effect that the temperature of the exhaust can be raised.

  Therefore, in the present embodiment, the temperature of the exhaust gas is increased by using the above-mentioned secondary effect in the starting advance angle state, thereby promoting the temperature increase in the vicinity of the air-fuel ratio sensor 18 in the exhaust passage 6, The water droplets in the vicinity of the air-fuel ratio sensor 18 evaporate and disappear at an earlier time after starting.

That is, in the present embodiment, even if the cooling water temperature of the internal combustion engine 1 is equal to or higher than the predetermined temperature described above, the temperature in the vicinity of the air-fuel ratio sensor 18 in the exhaust passage 6 is reduced by water droplets without operating the intake side VVT 17 and the exhaust side VVT 16. The water advance extinction temperature (= dew point temperature) at which the water vapor disappears is determined to continue the advance angle state at the start until the temperature becomes equal to or higher than Tw.

  FIG. 3 shows a flowchart of a VVT operation timing control routine in the present embodiment. This routine is a program stored in the ROM of the ECU 20 and is executed every predetermined period while the internal combustion engine 1 is powered on.

  When this routine is executed, it is first determined in S101 whether the internal combustion engine 1 has been started. Here, when it is determined that the internal combustion engine 1 has not been started, this routine is temporarily terminated. On the other hand, if it is determined that the internal combustion engine 1 has started, the process proceeds to S102.

In S102, the wall surface temperature Tssr of the exhaust passage 6 in the vicinity of the air-fuel ratio sensor 18 is estimated. Specifically, it is estimated from a cumulative intake air amount from the start of the internal combustion engine 1 using a predetermined empirical formula, which will be described in detail later. When the process of S102 ends, the process proceeds to S103.

  In S103, it is determined whether the estimated wall surface temperature Tssr of the exhaust passage 6 is equal to or higher than the water droplet extinction temperature Tw. Here, if it is determined that the temperature Tssr is equal to or higher than the water droplet extinction temperature Tw, the process proceeds to S104. On the other hand, if it is determined that the temperature Tssr is lower than the water drop extinction temperature Tw, the process proceeds to S105.

  In S104, the operation of the intake side VVT 17 and the exhaust side VVT 16 is started, and control for changing the opening / closing timings of the intake valve 12 and the exhaust valve 9 according to the operating state of the internal combustion engine 1 is started. In S105, the operation of the intake side VVT 17 and the exhaust side VVT 16 is stopped or the stopped state is continued. As a result, the advance angle state at the start is continued. When the process of S104 or S105 ends, this routine is temporarily ended.

As described above, in this embodiment, when the internal combustion engine 1 is started, the wall surface temperature Tssr of the exhaust passage 6 near the air-fuel ratio sensor 18 is estimated as the temperature near the air-fuel ratio sensor 18. Then, while the wall surface temperature Tssr is lower than the water droplet extinction temperature Tw at which water droplets disappear from the vicinity of the air-fuel ratio sensor 18 in the exhaust passage 6, the intake side VVT 17 and the exhaust side VVT 16 are not started and the start-up advance state is established. Continued. On the other hand, when the wall surface temperature Tssr of the exhaust passage 6 becomes equal to or higher than the water droplet extinction temperature Tw, the operation of the intake side VVT 17 and the exhaust side VVT 16 is started, and the intake valve 12 and the exhaust gas are exhausted according to the operating state of the internal combustion engine 1. The opening and closing timing of the valve 9 was optimized to improve driving performance and fuel consumption.

According to this, the temperature of the exhaust gas can be more positively raised at the start of the internal combustion engine 1 and the energization start timing of the air-fuel ratio sensor 18 to the sensor heater can be advanced. As a result, the air-fuel ratio feedback control can be started early when the internal combustion engine 1 is started, and the emission can be improved.

In the above control, the wall surface temperature Tssr is determined by the air-fuel ratio sensor 1 in the exhaust passage 6.
As long as the temperature is lower than the water droplet extinction temperature Tw at which the water droplets disappear from the vicinity of 8, the operation of both the intake side VVT 17 and the exhaust side VVT 16 is not started, and both the intake valve 12 and the exhaust valve 9 are kept in the advanced state at the start. It was. However, if at least the opening / closing timing of the exhaust valve 9 is continued, the advancement state at the time of starting is continued, so that a sufficient effect can be obtained in the present invention. Therefore, the above control may be applied only to the exhaust valve 9. Absent.

Next, a method for estimating the wall surface temperature Tssr of the exhaust passage 6 in the vicinity of the air-fuel ratio sensor 18 in S102 of the VVT operation timing control routine will be described with reference to FIGS. FIG. 4 is a graph showing the relationship between the integrated intake air amount at start-up and the wall surface temperature Tssr of the exhaust passage 6 in the vicinity of the air-fuel ratio sensor 18 in this embodiment. This graph was obtained by experiment. As shown in FIG. 4, the A region where the wall surface temperature Tssr is less than the first threshold temperature T1, the B region where the wall surface temperature Tssr is equal to or higher than the first threshold temperature T1 and less than the second threshold temperature T2, and the wall surface temperature Tssr is the second. In the C region that is equal to or higher than the threshold temperature T2, the relationship between the integrated intake air amount and the wall surface temperature Tssr is different.

The relationship between the wall surface temperature Tssr and the integrated intake air amount in each of the A region, the B region, and the C region is expressed by the following equation.
In area A,
Tssr = ega1sum × ΔA × kTHW (1)
In region B,
Tssr = ega1sum × ΔB × kGAS × kTHW (2)
In region C,
Tssr = ega1sum × ΔC × kTHW (3)
Here, ega1sum is an integrated intake air amount per 1 L of the exhaust amount of the internal combustion engine 1. ΔA, Δ
B and ΔC are proportionality constants obtained by experiments for each region. kGAS is a correction coefficient used particularly in the B region. kTHW is a correction coefficient determined by the cooling water temperature at the start. Further, the first threshold temperature may be a dew point temperature in the vicinity of the air-fuel ratio sensor 18 (for example, 54 ° C.). The second threshold temperature may be 60 ° C., for example.

FIG. 5 shows an example of the relationship between the correction coefficient kGAS and the intake air amount (ega1sum update amount per 100 ms) and the relationship between kTHW and the starting water temperature.

  Next, FIG. 6 shows a flowchart of a wall surface temperature estimation routine in the present embodiment. This routine is a program stored in the ROM of the ECU 20 and is executed every predetermined period while the internal combustion engine 1 is powered on.

  When this routine is executed, it is first determined in S201 whether the internal combustion engine 1 has been started. Here, if it is determined that the internal combustion engine 1 has not been started, the present routine is immediately terminated. On the other hand, if it is determined that the internal combustion engine 1 has been started, the routine proceeds to S202.

  In S202, the intake air amount is acquired. Specifically, it is acquired by reading the output signal of the air flow meter 13 into the ECU 20. If the process of S202 ends, the process proceeds to S203.

In S203, it is determined whether this routine is executed for the first time after the internal combustion engine 1 is started. Specifically, for example, a predetermined flag is set to 0 when the internal combustion engine 1 is stopped, and the flag is set to 1 after execution of the first routine after the internal combustion engine 1 is started. And in this process, you may determine by reading the value of the said flag into ECU20. Here, if it is determined that this is the first execution after the internal combustion engine 1 is started, the process proceeds to S204. On the other hand, if it is determined that it is not the first execution after the start, the process proceeds to S205.

In S204, the current wall surface temperature Tssr of the exhaust passage 6 is estimated. In this case, since it is the first execution after the internal combustion engine 1 is started, the wall surface temperature Tssr is once estimated using the expression (1) in the case of the region A. When the process of S204 ends, the process proceeds to S205.

In S205, the estimated current wall surface temperature Tssr of the exhaust passage 6 is the first threshold temperature T1.
It is determined whether or not this is the case. If a negative determination is made here, the process proceeds to S206. On the other hand, if a positive determination is made, the process proceeds to S207.

In S207, the current estimated wall surface temperature Tssr of the exhaust passage 6 is the second threshold temperature T2.
It is determined whether or not this is the case. If a negative determination is made here, the process proceeds to S208. On the other hand, if a positive determination is made, the process proceeds to S209.

And in each process of S206, S208, and S209, the value of wall surface temperature Tssr of the exhaust passage 6 is calculated using Formula (1), (2), (3), respectively. Note that the value of the integrated intake air amount is obtained by integrating the intake air amount value acquired in S202 at each execution of this routine. When the processes of S206, S208, and S209 are completed, this routine is temporarily ended.

As described above, in the present embodiment, the wall temperature Tssr of the exhaust passage 6 near the air-fuel ratio sensor 18 obtained in advance is obtained using the experimental formula obtained in advance from the integrated intake air amount. The temperature near the air-fuel ratio sensor 18 can be obtained more accurately without using a temperature sensor or the like.

In the above embodiment, the wall surface temperature Tssr of the exhaust passage 6 is estimated as the temperature in the vicinity of the air fuel consumption sensor 18, but the temperature in the vicinity of the air fuel consumption sensor 18 is the temperature of the exhaust itself in the vicinity of the air fuel consumption sensor 18. Other temperatures may be employed. Moreover, you may make it detect the actual temperature of the air-fuel-consumption sensor 18 vicinity using a temperature sensor.

It is a figure which shows schematic structure of the internal combustion engine in the Example of this invention, its intake / exhaust system, and a control system. It is a figure for demonstrating the opening-and-closing timing of an intake valve and an exhaust valve in the conventional starting advance angle state. It is a flowchart about the VVT operation timing control routine in the Example of this invention. It is a figure which shows the relationship between the integrated intake air amount in the Example of this invention, and the wall surface temperature estimated value of the exhaust passage near an air fuel ratio sensor. It is a graph shown about the change of each correction coefficient in the estimation formula of the wall surface temperature of the exhaust passage in the Example of the present invention. It is a flowchart about the wall surface temperature estimation routine in the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder 3 ... Piston 4 ... Connecting rod 5 ... Intake passage 6 ... Exhaust passage 7 ... Exhaust gas purification device 8 ... Exhaust port 9 ... Exhaust valve 10 ... Fuel injection valve 11 ... Intake port 12 ... Intake valve 13 ... Air flow meter 14 ... Throttle valve 16 ... Exhaust side VVT
17 ... Intake side VVT
20 ... ECU

Claims (4)

An air-fuel ratio sensor provided in an exhaust passage of the internal combustion engine and capable of detecting an air-fuel ratio of exhaust in a state activated by heating;
A start time advance means for setting the open / close timing of the exhaust valve at the start of the internal combustion engine to a start time open / close timing that is an advance side of a reference open / close timing that is a reference of the open / close timing of the exhaust valve after completion of warm-up;
A variable valve mechanism capable of changing the opening and closing timing of the exhaust valve;
An operating state corresponding control means for performing an operating state corresponding control for changing the opening and closing timing of the exhaust valve by the variable valve mechanism according to the operating state of the internal combustion engine;
Temperature obtaining means for obtaining a temperature in the vicinity of the air-fuel ratio sensor in the exhaust passage,
When the temperature in the vicinity of the air-fuel ratio sensor acquired by the temperature acquisition means at the time of starting the internal combustion engine is lower than the dew point temperature at which water drops in the exhaust passage disappear, the opening / closing timing of the exhaust valve is set at the time of starting. Maintained at the opening and closing time,
The control apparatus for an internal combustion engine, wherein the operation state correspondence control unit starts the operation state correspondence control after the temperature in the vicinity of the air-fuel ratio sensor becomes equal to or higher than the dew point temperature . 2. The control device for an internal combustion engine according to claim 1, wherein energization of the sensor heater of the air-fuel ratio sensor is started after the temperature in the vicinity of the air-fuel ratio sensor becomes equal to or higher than the dew point temperature .   3. The control device for an internal combustion engine according to claim 1, wherein the temperature acquisition unit estimates a temperature in the vicinity of the air-fuel ratio sensor in the exhaust passage from an integrated intake air amount of the internal combustion engine.   The temperature acquisition means estimates the temperature in the vicinity of the air-fuel ratio sensor in the exhaust passage from the integrated intake air amount of the internal combustion engine and the cooling water temperature at the start of the internal combustion engine. The internal combustion engine control device described.

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